For the "Tricks and Treats..." series of achievements, I recommend installing the add-on Candy Buckets (Hallow's End). It adds small candy bucket icons to your world map, and even knows and remembers buckets you've visited! It has TomTom (and TomTomLite for those users) integration, too. Spiffy!

Last year, the candy bucket for Mistfall Village required players to be in the correct phase of the zone. (Once the player is able to do the dailies for Golden Lotus, the candy bucket becomes visible.) However, as of Patch 5.4, the Golden Lotus faction is dead and all GL quests not tied to certain achievements were removed from the game. It will be interesting to see if it is still phased.